University of Missouri Extension | Updated: May 16, 2012
How do you estimate hay moisture levels in the field? Veteran hay raisers have their own tricks which may involve twisting a handful or kicking the window to see if it “rattles.” There are more accurate methods for beginners such as moisture meters. There’s also the more time consuming method that involves a microwave oven, a scale and math.
A lot of hay is wasted or lost due to being baled too wet for dry hay or too wet or too dry if you’re putting it in a bag or inline tube wrappers. Hay barns are also in danger when hay is baled much above 20 percent moisture and put in a barn.
Some folks may think a good way to protect “dry” hay is to cover it completely with plastic. That’s risky as the stack does need air to reduce moisture levels. Remember big rounds should be drier then small squares to reduce mold formation.
A final tip from the February letter, don’t set outside stored big bales under trees! Find a location in full sun where the bales can dry out and not remain damp.
Barn fires
Storing hay in barns still makes sense, but especially with big round bales be careful of putting the hay in while it’s still heating. A general recommendation is to leave the hay in the field a couple weeks until the internal temperature of the bale has stabilized or is decreasing.
The guidelines for temperatures generally say there’s very little risk as long as the temperature internally stays below 120 degrees F. One reference states that if you don’t have a thermometer, drive a steel rod into the bale and leave it there for 15 minutes or more. If the rod is too hot to handle when it’s removed, the temperature is likely above 120 degrees.
The real concern that the hay is approaching a high risk temperature is when it exceeds 170-180 degrees. That’s when you call the fire department. At that temperature it can rapidly rise to 400 degrees or more and cause a fire.
